Comparison between numerical modeling and experimental measurements of the interface shape in Kyropoulos growth of Ti-doped sapphire crystals

Stelian, Carmen; Sen, Gourav; Barthalay, Nicolas; Duffar, T.

doi:10.1016/j.jcrysgro.2016.08.001

Cited by 19 publications

(6 citation statements)

References 8 publications

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“…They are many differences in the growing process between Czochralski and Kyropoulos. The crystallization takes place in the melt with a highly convex crystallization interface [31]. This interface shape coupled with the segregation effect induces is responsible to a strong gradient of Ti concentration in the crystal [32].…”

Section: Discussionmentioning

confidence: 99%

Scattering defect in large diameter titanium-doped sapphire crystals grown by the Kyropoulos technique

et al. 2018

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Section: Discussionmentioning

confidence: 99%

Scattering defect in large diameter titanium-doped sapphire crystals grown by the Kyropoulos technique

et al. 2018

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“…The finite element software COMSOL-Multiphysics® was used for modelling the Kyropoulos growth of the Ti-doped sapphire crystals of interest. The model and the results are already published, in terms of temperature field and solid-liquid interface shape [28], Ti segregation [29] and stresses in the growing crystal. The reader may refer to figure 3 in [30] where a von Mises stress map in the growing crystal is shown, as well as stress variation along the crystal radius at several crystal lengths.…”

Section: Numerical Modelling Of Stresses In the Growing Crystalmentioning

confidence: 99%

Origin of scattering defect observed in large diameter Ti:Al2O3 crystals grown by the Kyropoulos technique

Sen

Alombert-Goget

Nagirnyi

et al. 2020

Journal of Crystal Growth

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“…The heat removed at the growth interface due to the crystal pulling and, respectively, the latent heat released during the solidification process, are included in the present model. More details about the numerical model are given in our previous works …”

Section: Model Descriptionmentioning

confidence: 99%

Modeling Interface Shape in Czochralski Growth of Sapphire Crystals

Stelian

Duffar

2017

Crystal Research and Technology

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Numerical modeling is applied to investigate the factors affecting the shape of the crystal-melt interface in Czochralski growth of sapphire crystals having 10 cm in diameter. The modeling is performed for a 2D -axisymmetric furnace configuration, where all the furnace components are included. The shape of the crystal-melt interface is computed by using the deformable mesh technique. Numerical results show that the conical shape of the interface depends essentially on the internal radiative heat exchanges in the semi-transparent sapphire crystal, being less influenced by the buoyancy convection. The Marangoni effect enhances the flow near the triple solid-liquid-gas point, leading to convex-concave shape of the growth interface, which is prone to facet formation. Numerically computed shape of the interface is compared to experimental results taken from literature. Applying crystal/crucible rotation has a significant impact on the flow pattern and the shape of the growth interface. Computations performed by applying only crystal rotation at rates higher than a critical value, show a reversed convection at the sample centre, underneath the crystal. This flow affects the shape of the interface, which is less curved and exhibits a convex shape. If the rotation rate is too much increased, the interface shape can be distorted by the intense flow. Application of crucible rotation intensifies the downward flow at the sample centre, leading to increased interface curvature. Rotating both the crystal and crucible in opposite directions generates a complex flow pattern, but has no flattening effect on the interface.

show abstract

Comparison between numerical modeling and experimental measurements of the interface shape in Kyropoulos growth of Ti-doped sapphire crystals

Cited by 19 publications

References 8 publications

Scattering defect in large diameter titanium-doped sapphire crystals grown by the Kyropoulos technique

Scattering defect in large diameter titanium-doped sapphire crystals grown by the Kyropoulos technique

Origin of scattering defect observed in large diameter Ti:Al2O3 crystals grown by the Kyropoulos technique

Modeling Interface Shape in Czochralski Growth of Sapphire Crystals

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